1. Field of the Invention
The present invention relates to a color image forming apparatus for sequentially forming images with a plurality of image forming units and more particularly to a color image forming apparatus capable of recycling collected toners as far as possible to thereby promote effective use of toner.
2. Description of the Background Art
Today, a copier, printer, facsimile apparatus or similar image forming apparatus is often configured to recycle collected toner for saving limited resources. A problem with a full-color image forming apparatus, which uses yellow toner, magenta toner, cyan toner and black toner, is that the toners of different colors are mixed in cleaning units. When more than preselected amounts of toners of different colors are mixed, the tones of colors vary. Further, the toners each having a particular charging characteristic are selectively scattered around. Image quality is therefore degraded unless only toners with low degrees of color mixture are recycled.
Various technologies have heretofore been proposed to recycle collected toners or to dispose of them. However, there has not been proposed a technology for promoting reliable toner recycling by determining whether or not to recycle collected toners and then efficiently selecting recycling or disposal. It is therefore likely that wasted toners contain recyclable toners or that toners not suited for recycling are recycled.
Technologies relating to the present invention are disclosed in, e.g., Japanese Patent Laid-Open Publication Nos. 8-286511, 9-6202, 2000-66559 and 2000-89633.
It is an object of the present invention to provide an image forming apparatus capable of using only part of collected toners that is suited for recycling.
An image forming apparatus of the present invention includes a recycle toner conveying device for returning toner collected in a cleaning step to a developing device as recycled toner. A waste toner conveying device conveys the collected toner to a waste toner container as waste toner. A switching devices selects either one of the recycle toner conveying device and waste toner conveying device.